All, I'm new to MQSeries and studied the code which uses messaging using IBM MQ. The code includes the jar of "com.ibm.mq" and issues API call to the put and read the messages from queues. The client does NOT issue any JNDI calls to connect to the host.The host I suppose is MQServer. The client initialzes the property structure with host,port, channel etc. Then client issues only API calls thr' "MQQueueManager" to access the queues and puts the messages by "MQMessage" class calls. My doubt is : Is it NOT neccssary to install MQClient here? If messaging can be achieved by APIs then MQClient is required in which cases, why?